Surface operated, subsurface safety valve assembly

ABSTRACT

Opening and closing of a subsurface safety valve in a well tubing is regulated by control pressure supplied to the valve through a pressure passage extending from the valve to the well surface. Reduction in control pressure in the passage permits the valve to move to its normally closed position under the influence of a compressed spring. Repressuring the passage acts through an expansion chamber to reopen the valve against the force of the spring. A pressure bypass is provided for equalizing pressures above and below the closed valve to ease reopening of the valve. The valve may be permanent or retrievable, and in one form of the invention, a retrievable valve is landed within an inoperative, permanent safety valve. In the latter embodiment, means are provided for regulating opening and closing of the retrievable valve by pressure supplied through the pressure passage previously regulating operation of the permanent valve. In one form of the invention, the passage is provided by a small control line and in another form, the passage is provided between two concentric tubing strings.

United States Patent [191 Dinning 1 SURFACE OPERATED, SUBSURFACE SAFETYVALVE ASSEMBLY Robert W. Dinning, Houston, Tex.

[73] Assignee: Brown Oil Tools, Inc., Houston,

Tex.

[22] Filed: Dec. 27, 1971 [21] Appl. No.: 211,906

[75] Inventor:

[52] 11.8. CI. 166/72, 166/224 S .1 /a i? i [5 7] ABSTRACT Opening andclosing of a subsurface safety valve in a well tubing is regulated bycontrol pressure supplied to the valve through a pressure passageextending from the valve to the well surface. Reduction in controlpressure in the passage permits the valve to move to its normally closedposition under the influence of a compressed spring. Repressuring thepassage acts through an expansion chamber to reopen the valve againstthe force of the spring. A pressure bypass is provided for equalizingpressures above and below the closed valve to ease reopening of thevalve. The valve may be permanent or retrievable, and in one form of theinvention, a retrievable valve is landed within an inoperative,permanent safety valve. In the latter embodiment, means are provided forregulating opening and closing of the retrievable valve by pressuresupplied through the pressure passage previously regulating operation ofthe permanent valve. In one form of the invention, the passage isprovided by a small control line and in another form, the passage isprovided between two concentric tubing strings.

18 Claims, 18 Drawing Figures PATENTED BET 9 75 SHEEI REF 5 ATTOENV5PATENTEU BET 9 75 SHEF u UF 5 SEQ kg ATTOENEYS V SURFACE OPERATED,SUBSURFACE SAFETY VALVE ASSEMBLY BACKGROUND OF THE INVENTION 1. Field ofthe Invention The present invention relates to automatic valving meansemployed to terminate the flow of fluids through a well structure. Morespecifically, the present invention relates to a subsurface safety valvewhich is controlled from the well surface to close in the event ofdamage to the confining structure at the wellhead.

2. Description of the Prior Art The prior art conventionally employssurface operated subsurface valves which open or close a productiontubing string in response to hydraulic pressure supplied through a smallcontrol line extending between the subsurface valve and the wellsurface. In operation, loss of pressure in the control line, which maybe caused by damage to the wellhead structure and the attached controlline, permits a spring loaded valve in the production tubing string tomove to closed position to terminate the flow of well effluents throughthe string. An example of this type valve is illustrated in U. S. Pat.No. 3,092,135.

Where such valves are in-place or permanent valves forming a fixed partof the production tubing string, replacement or repair of the valverequires removal of the entire tubing string. The expense and lostproduction time associated with complete removal of the tubing stringare highly undesirable. Normally, inplace valves are desirable to theextent that they afford the use of large flow passages through the valveelements.

Another problem associated with surface operated, subsurface safetyvalves of the type previously described is that once closed, such valvesare difficult to reopen because of the pressure differential developedacross the valve closure elements. Customarily, to reopen such valves,it is necessary to repressure the production tubing string from thewellhead until the pressures above and below the closure elements areequalized. I

In some applications, it may not be desirable to employ a separate,small control line which extends from the subsurface valve to'the wellsurface. Such use may be undesirable for example where production isbeing effected simultaneously through several zones and the small lineis carried in the annular area used to produce one of the zones. Flow ofsandy effluents through the annular area may eventually cut through thecontrol line permitting loss of pressure which in turn would causeclosure of the subsurface valve.

SUMMARY OF THE INVENTION In the preferred form of the invention, anin-place or permanent surface operated, subsurface safety valve assemblyis designed to act as a landing nipple for a re trievable subsurfacevalve assembly whereby the retrievable valve may provide the safetyvalving function previously supplied by the in place-valve. In thismanner, the desired subsurface safety function may be restored withoutthe need for complete removal of the production tubing string.

In the latter embodiment, both the in-place valve and the retrievablevalve are equipped with pressure bypasses which permit equalization ofpressure above and below the closed valve elements so that the controlpressure is sufficient to reopen the valve.

In one form of the invention, the control pressure passage is formed inthe annular space included between two concentric tubing strings whichextend between the subsurface valve location and the well surface. Inthe latter embodiment, a retrievable valve mechanism is movable throughthe central tubing string and is operable by hydraulic pressure suppliedthrough the annular control passage to terminate effluent flow throughthe internal tubing string.

From the foregoing it may be appreciated that one object of the presentinvention is to provide an inplace, subsurface, surface-operated safetyvalve which, in the event it should become inoperable, may function as alanding nipple for a retrievable valving assembly which is also surfaceoperated.

Another object of the present invention is to provide a control pressurepassage in the form of an annular space formed between two concentrictubing strings exending between the subsurface valve and the wellsurface.

Still another object of the present invention is to provide a pressureequalizing means whereby high pressure differentials existing acrossclosed valve members may be equalized to permit the subsurface valve tobe easily reopened.

The foregoing objects of the invention and other features and advantagesof the invention will be more readily appreciated from the followingspecification, drawings and the related claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B are elevations, inquarter section, illustrating the upper and lower portions respectivelyof one form of the surface-operated, subsurface valve assembly of thepresent invention;

FIGS. 2A and 2B are the upper and lower portions respectively ofthevalve assembly of FIG. 1 in open position;

- FIGS. 3A and 3B are vertical quarter sections of the upper and lowerportions respectively of the assembly of FIG. 1 illustrating a lock-outmechanism conditioning the assembly for receipt ofa second valveassembly;

FIGS. 4A and 4B are similar to FIGS. 3A and 3B illustrating theoperation of the lock out mechanism;

FIGS. 5A and 5B illustrate a retrievable valve assembly landed in theassembly of FIG. 1;

FIGS. 6A and 6B are similar to FIGS. 5A and 5B, illustrating theretrievable valving assembly in open position;

FIGS. 7A and 7B are vertical quarter sections illus trating the upperand lower portions respectively of a modified valve assembly illustratedin closed position;

FIGS. 8A and 8B are vertical quarter sections illustrating the upper andlower portions respectively of another modification of the presentinvention employing an annular pressure control passage; and I FIGS. 9Aand 9B illustrate the assembly of FIG. 8 in open position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS One form of the presentinvention is illustrated in FIGS. IA and 18 which show the upper andlower portions, respectively, of a surface-operated, subsurface safetyvalve assembly indicated generally at Ill. The assembly is includedaspart of a production tubing string T which extends between a wellhead(not illustrated) and a subsurface petroleum bearing formation (notillustrated) to convey effluents in the formation to the well surface ina well-known manner. The assembly 10 includes a plural part outerhousing body formed by tubular members 11, 12, 13, 14 and 15 which arethreadedly connected to each other to form a composite tubular bodywhich is connected at its upper and lower ends into a production tubingstring T. .O-ring seals are disposed between the mating parts in theouter housing to prevent leakage.

A primary tubular control sleeve 16 carried internally of the outerhousing is adapted to be moved axially through the housing to regulateopening and closing ofa flapper valve closure assembly indicatedgenerally at 17. The control sleeve 16 is formed from upper and lower,threadedly engaged segments 18 and 19. A coil spring 20 extendsconcentrically within an annular space 21 formed between the lowersleeve section 19 and the outer housing member 13. The spring 20 iscompressed axially between the base of upper sleeve section 18 and theupper end of housing section 14 and biases the sleeve 16 upwardly.

The valve assembly 17 is carried in the outer housing member 14 andincludes a flapper closure member 22 which is pivotably mounted about asupporting pin 23. A spring 24 encircles the pin 23 and biases theclosure member 22 to closed position. In its closed position, an O-ringseal 25 carried on the sealing surface of the flapper element 22 engagesand seals agianst an annular seat member 26 carried in the housingmember 14. A recess 27 formed along the internal surface of the housingcomponent 14 receives the flapper element 22 when the flapper is rotatedinto its open position illustrated in FIG. 2B.

In operation, hydraulic pressure is supplied to the assembly 10 througha small control line 28 which is in pressure communication with a port29 formed through the housing component 12. Hydraulic fluid in the line28 flows through the base of the line into the port 29 where it iscommunicated to an expansion chamber 30 formed between the housingmember 12 and the control sleeve segment 18. Upper and lower O-ringseals 31 and 32, respectively, form a sliding seal between the controlsleeve component 18 and housing component 12. The cross-sectional areaof the sliding seal formed by the O-ring 31 is less than that of the0-ring 32 with the result that the control sleeve 16 is moved axiallydownwardly through the outer housing when the fluid pressure in thechamber 30 is sufficiently greater than the external pressure tocompress the spring 20.

The initial downward movement of sleeve 16 from the position illustratedin FIGS. 1A and 18 moves an O-ring seal 33 out of sealing engagementwith the internal surface .of the housing member 12 to open a bypasswhich permits equalization of pressures existing above and below theclosed flapper valve 22. In operation, the bypass functions tocommunicate the pressure in the assembly 10 below the flapper valve 22through an axially extending opening 34 formed in the housing component14 to a bypass line 35 which is in pressure communication with a port 36opening through the housing component 12 to an annular space 37 formedbetween the control sleeve 16 and the surrounding outer housing. Withthe seal 33 below the base of member 12, the pressure in the annularpassage 37 is communicated through a radial port 38 into the assembly 10abu the flapper valve 22.

Initially, the pressure supplied through the control line 28 issufficient to lower the control sleeve 16 enough to release the sealformed by O-ring 33 so that fluid pressure below the flapper valve 22 isbypassed around the valve. The sleeve 16 is retained in this positionuntil the pressures above and below the flapper element 22 aresubstantially equal at which point, the pressure in chamber 30 issufficient to compress the spring 20 causing the sleeve 16 to moveaxially downwardly until it engages the flapper 22. The downwardlymoving sleeve rotates the flapper about the pin 23 into the recess 27.When the sleeve 16 is shifted to its lowermost position, the valveassembly 10 is fully opened as illustrated in FIGS. 2A and 2B. In thelatter position, the control sleeve segment 19 engages an O-ring seal 39carried in a seal 40 so that the sealing surfaces on the flapper element22 and seat member 26 are protected from the abrading and corrosiveeffects which may be caused by well effluents flowing through theassembly 10.

In use, the assembly 10 is normally maintained in its open position asillustrated in FIGS. 2A and 2B. In the event pressure supplied throughthe line 28 is lost, as may occur for example from wellhead damage, thepressure in chamber 30 falls sufficiently to permit the spring 20 toshift the sleeve 16 upwardly permitting the spring 24 to swing theflapper element 22 into the closed position illustrated in FIG. 1B. Whenin the closed position, all effluent flow through the tubing string T isterminated. When the wellhead damage or malfunction has been corrected,the valve 17 may be reopened by repressuring the line 28 to shift thesleeve 16 downwardly sufficiently to open the pressure bypass around thevalve in the manner previously described. Subsequently, with thepressure across the flapper equalized, the pressure in control line 28is sufficient to snap the flapper 22 into the fully opened positionillustrated in FIG. 2B.

The valve assembly 10 is maintained in its open position when it isinitially being run into the well by pressuring the chamber 30 at thewell surface. While pressure is being supplied to the chamber 30, theassembly 10 is inverted which permits a ball 41 to rest and seal againstan annular O-ring seal 42 carried in a seating surface 43 formed at thebase of the pressure line 28. When the pressure being supplied throughline 28 is released, the back pressure in chamber 30 maintains the ball41 against the O-ring 42 so that the ball acts as a check valve whichprevents loss of pressure in the chamber 30 and maintains the valve 17in open position. Once the valve assembly has been lowered to itssubsurface position, pressure supplied through the line 28 permits theball 41 to fall to the bottom of an axial retaining bore 44 formed inthe housing member 22.

In the event the valve assembly 17 should become inoperative, theassembly 10 is adapted to receive a second, retrievable,surface-operated safety valve. The assembly 10 is conditioned to receivethe retrievable valve by a surface operated lock-down mechanismindicated generally at 45 in FIGS. 3 and 4. Referring initially to FIG.3, the mechanism 45 is designed to shift the sleeve 16 to its lowermostposition and to lock it in that position by shifting a hold-down collar46 downwardly through the outer housing body. To this end, the lock-downmechanism 45 is lowered through the tubing string T into the positionillustrated in FIGS. 3A and 3B. The required axial movement of theassembly 45 may be regulated from the surface by any suitable means,including wireline, hydraulic pumping means, or otherwise.

The assembly 45 includes a rod 47 having an enlarged foot piece 48secured at its lower end. The upper end of the rod 46 is threadedlyengaged with a rod section 49 which is in turn engaged at its upper endto a turular member 50. A connector member 51 is secured by means of ashear pin 52 within the upper tubular opening of rod member 50. Theupper end of component 51 connects to a conventional wireline (notillustrated) which is employed to return the assembly 45 to the wellsurface.

In the preferred form, the assembly 45 is pumped into position from thewellhead and for this purpose, suitable annular packing 53 is carriedabout the external surface of the component 50. The packing 50cooperates with'an internally positioned O-ring seal 54 to provide apressure barrier in the tubing string T. Pres.- sure applied from thewell surface above the pressure barrier pumps the assembly 45 downwardlythrough the tubing string T until one or more spring loaded dogs 55register with locating recesses 56 and 57 formed along the internalsurface of the housing member 15. In the latter position, springs 58snap the dogs 55 radially outwardly so that projections 59 and 60 on thedogs spring into the recesses 56 and 57, respectively. The dogs 55 arepivotably carried in a tubular support body 61 which forms the lower endof a composite sleeve 62. The sleeve- 62 includes a second tubular bodyportion 63 which is pinned to an upper tubular portion 64 by means of ashear pin 65. An externally developed projection 66 at the base ofmember 64 engages an internally developed projection 67 at the upper endof a component 63 to prevent the two components from separating. Theupper end of the sleeve 62 is threadedly engaged to a tubular holdingcomponent 68.

When the assembly 45 has been pumpedto the subsurface locationillustrated in FIGS. 3A and 3B, the dogs 55 spring open in the mannerdescribed to release the foot piece 48- which had been trapped in aninternal recess 69 formed along the radially inner surface of the dogs55. When thus located and with the rod 47 re leased, the mechanism 45 israised by an upward pull exerted by the surface extending wirelineconnected to the top of the mechanism. A compressed coil spring 71encircling the rod 47 urges the rod upwardly and the sleeve 62downwardly when the wireline is raised. The action of the spring 71cooperates with the partial locking provided by the dogs 55 to permitthe rod 47 to be moved upwardly through the sleeve 62. Upward movementof the rod through the upper sleeve section 38 permits one or morespring loaded dog members 72 to spring radially outwardly under theinfluence of a U- type spring 73. A lower projection 74 extendingdownwardly from the base of the dogs 72 engages an upwardly extendinglip 75 on the sleeve component 68 to limit the outward radial expansionof the dogs 72. Upward movement of the rod through the sleeve component68 also compresses a snap ring 76 which permits the rod to be raisedabove a shoulder 77 exending radially inwardly from the sleeve component68. The flat FIG. 4A illustrates the dog 72 extending radially outwardlyand the rod 47 shifted upwardly with respect to the surrounding sleevecomponent 68. When in the expanded position, a downwardly directed face78 on the dog 72 engages the top of the lock-down collar'46. Thelock-down collar includes a plurality of upwardly extending resilientcollet fingers 79 having enlarged locking heads 80 at their upper end.When the valve 17 is functioning properly, the heads 80 lock with anannular recess 81 formed along the internal wall of the housing member11 to maintain the collar in the position illustrated in FIGS. 1A and2A. With the dogs 72 extended as illustrated in FIG. 4A, the assembly 45is driven downwardly by hydraulic pressure applied from the wellhead orby suitable jarring mechanisms (not illustrated), or otherwise, to shiftthe hold-down collar 46 from the position illustrated in FIG. 1A to thelower position illustrated in FIG. 4A. The downward force acts throughthe snap ring 76 against the top of projection 77. When the forceexerted on sleeve 62 is sufficiently great, the pin 65 shears permittingthe sleeve segments 64 and 68 to shift downwardly from the positionillustrated in FIG. 4A. Downward movement of the lower portions ofsleeve 62 is prevented. by engagement of a lower face 82 formed alongthe base of the dogs 55 with a flat face 83 formed at the lower end ofthe locating recess 57. Downward shifting of the locking collar. 46

, brings the collet heads 80 into engagement with an annular recess 84formed in the internal wall of the outer housing. Lowering of thehold-down collar 46 is also effective to shift the operating sleeve 16downwardly into the position illustrated in FIG. 4A. The collet headsare provided with flat upper surfaces which engage the flat uppersurface of the recess 84 to prevent the collar 46 and sleeve 16 fromshifting upwardly under the influence of the coil spring 20. I

With the sleeve 16 thus locked into its lower position, the lock-downassembly 45 may be withdrawn to the well surface. Raising of the surfaceextending wireline draws the rod 47 and sleeve segments 68 and 64 upwardly until the projection 66 engages projection 67 which draws thelower portion of the sleeve 62 upwardly. With the projections 66 and 67engaged, the foot piece 48 aligns with the recess 69 and the upward pullexerted on thersleeve 62 draws tapered surfaces on the dogs 55 andrecesses 56 and .57 into engagement causing the dogs to close radiallyinwardly against the spring force to permit the entire mechanism 45 tobe withdrawn to the well surface.

If a pressure differential develops across the seal 54 and packing'53 asthe mechansim 45 is being raised through the tubing T, the shear pin 52severs permitting an enlarged base section 85 at the bottom ofconnecting member 51 to move up to and engage an internal shoulder 85formed at the top of tubular rod member 50. In the latter position, theseal provided by O-ring 54 base of thering 76 engages the top ofprojection 77 and prevents the rod from returning to its originalposition.

is disrupted and fluid above the assembly 45 is permitted to flowthrough axial openings 86 and radial openings 87 to prevent developmentof a pressure differential across the upwardly moving mechanism 45.

Once the sleeve 16 has locked in its lower position in the mannerpreviously described, a suitable perforating mechanism (not illustrated)is lowered through the tubing string T and operated to form one or moreperforations 88 (FIG. 5A) through the wall of control sleeve 16.Following formation of the perforations, a retrievable, surface operatedsafety valve assembly indicated generally at 89 in FIGS. A and 5B islowered through the tubing string T and landed within the assembly 1. Asuitable running tool (not illustrated) is employed to lower theretrievable assembly 89 into position and anchor it within thesurrounding outer housing of assembly 10. In operation, the assembly 89is designed to provide the same valving function previously provided bythe assembly 10 with opening and closing of the valve controlled bypressure in the control line 28.

The valve assembly 89 includes a main body housing formed of threadedlyengaged tubular members which include a lower dog holding member 90, avalve mounting member 91, a spring housing member 92, a connectingmember 93, a chamber housing member 94, an upper connecting member 95, alocking dog carrying member 96 and an upper retrieving member 97. Ateach of the threadedly engaged junctions of the members forming the mainbody housing, O-ring sals are provided to ensure fluid-tight engagementbetween the components.

An axially movable, secondary control sleeve 98 is carried within themain body housing. A coil spring 99 concentrically positioned betweenthe control sleeve 98 and the main housing functions to bias the sleeve98 toward its upper axial position in the manner previously describedwith reference to spring 20. Axial movement of the sleeve 98 through themain housing body opens and closes a flapper valve assembly indicatedgenerally at 100.

Control of the opening and closing of assembly 89 is similar to thatpreviously described with reference to the assembly 10. Pressure in theline 28 is conveyed through the perforations 88 and through raidal ports101 to an expansion chamber 102. Fluid in the annular area between thesleeve 16 and the main housing body is confined at the upper end of thearea by an annular O-ring seal 95a and at the lower end of the annulararea by O-rings 91a and 39. When the pressure in the chamber 102 isgreat enough to overcome both the external pressure and the forceexerted by compressed spring 99, the sleeve 98 is shifted downwardlyinto the position illustrated in FIGS. 6A and 6B. In the latterposition, the valve assembly 100 is in its fully open position where itis received in a recess shielded by the overlying secondary operatingsleeve 98. In the event pressure in the line 28 is lost, the force ofspring 99 returns the sleeve 98 to its upper position permitting aspring 103 to pivot a flapper valve closure member 104 into the closedposition illustrated in FIG. 5B.

A pressure bypass is provided for reopening the valve 100. The bypassmeans includes O-ring seals 105 and 106 positioned respectively aboveand below radial port 107 extending through the wall of the sleeve 98and a radial port 108 extending through the valve mounting member 91below the O-ring 106 and above a third O-ring 109. With the valve in theclosed position illustrated in FIG. 5B, the flapper element 104cooperates with O-rings 109 and O-ring 91a to terminate effluent flowthrough the assembly. Repressuring the fluid in line 28 shifts thesleeve 98 downwardly bringing the port 107 below O-ring 106 to establisha pressure bypass through the ports 107 and 108. Pressure above andbelow the flapper 104 begins to equalize through the bypass and when thepressure differential across the flapper is substantially eliminated,the pressure exerted in chamber 102 is sufficient to snap the sleeve 98downwardly into the position illustrated in FIG. 6B.

During the initial placement of the assembly 89 within the assembly 10,spring loaded dogs 111 spring radially outwardly into the locatingrecesses 56 and 57 when the assembly is properly positioned axially.Movement below this point is prevented by a flat lower surface 112 onthe dogs 111 which engages the lower face 83 of recess 57.

At the upper end of assembly 89, an axially movable locking collar 113is employed to shift locking dogs 114 radially outwardly into an annularrecess 115. The collar 113 includes a snap ring 116 which is heldaxially below an internal shoulder 117 formed on the retrieving head 96while the assembly 89 is lowered downwardly through the tubing string.When the collar 113 is in the latter position, recesses 118 and 119formed along the external surface of the collar coincide with internallydirected projections 120 and 121 respectively formed on the locking dogs114 permitting the dogs to remain retracted. When the desired subsurfacelocation is reached, the running tool is manipulated to draw the collar113 axially upwardly with respect to the stationary main housing bodycausing the snap ring 116 to be depressed radially inwardly as it isbeing raised above the shoulder 117 permitting the collar to move intothe position illustrated in FIG. 5A. The upward movement of the collar113 with respect to the locking dogs 114 draws tapered surfaces at theends of recesses 118 and 119 against oppositely tapered surfaces on theprojections 120 and 121 to force the locking dogs 114 radially outwardlyinto locking engagement with the annular recess 115. With the dogs 114in the latter locking position, the assembly 89 is anchored axiallywithin the assembly 10.

Once the assembly 89 is locked in place, a shear pin 122 connecting thecollar 113 with the running tool is severed to permit the running toolto be returned to the surface. The snap ring 116 prevents the sleeve 113from falling axially below the projection 117 so that the dogs 114 aremaintained in their radially outer position.

In the event it become necessary to retrieve the assembly 89 for anyreason, a suitable retrieving mechanism (not illustrated) is loweredinto the tubing string T and latched onto a retrieving shoulder 123formed along the internal surface of the retrieving member 97.

The retrieving mechanism shifts the collar 97 down-- wardly, until thesnap ring 116 is below the projection 117, which permits radialretraction of the locking dogs 114. Once the dogs 114 have been freedfrom engagement with the recess 115, the assembly 89 may be withdrawn tothe surface.

FIGS. 7A and 7B illustrate the upper and lower portions respectively ofa modified surface operated subsurface safety valve assembly indicatedgenerally at 110. The assembly is similar in construction and operationto the assembly 10. The assembly 110 includes an outer assembly housing111 and an internal operating sleeve 112. Axial movmeent of the sleeve112 through the housing 111 regulates opening and closing of a flappervalve assembly indicated generally at 113. Fluid pressure forcontrolling movement of the sleeve 112 is supplied from the well surfacethrough a control line 114. Pressure in line 114 is communicated to anexpansion chamber 115. The upper and lower ends of thechamber are sealedby O-ring seals 116 and 117, respectively, which form a continuous,sliding sealingengagement between the sleeve 112 and the surroundinghousing 111. Pressure supplied to the chamber 115 shifts the sleeve 112downwardly to compress a coil spring 117 and close the flapper valve112. Loss of pressure in the chamber 115 permits the coil spring toreturn the sleeve 112 upwardly permitting a spring loaded flapperelement in valve 113 to snap to closed position. A port 118 formedthrough the wall of the sleeve 112 communicates with the annular spacebetween the sleeve 112 and the main housing 111 to prevent a fluid lockfrom developing during axial movement of the sleeve.

The assembly 110 is equipped with a pressure bypass means providedbyaxially spaced O-ring seals 119 and 120 and a flow passage 121 formedthrough the housing 111. When the assembly is in the positionillustrated in FIG. 7B, the flow passage 121 is blanked off between theO-rings 119 and 120. With pressure reestablished in the chamber 115, thesleeve 112 is shifted downwardly to bring a radial port 122 formedthrough the wall of the sleeve 112 below the O-ring 119 and into fluidcommunication with the passage 121. In the latter position of thesleeve, pressures above and below the flapper element equalizepermitting the pressure in chamber 115 to shift the sleeve 112 to itslowermost axial position.

When the assembly 110 becomes inoperative, a lock down tool is employedto shift a lock down collar 123 downwardly until locking heads 124formed at the base of the collar latch into a recess 25 formed along theinternal wall of the outer housing 111. With the collar 123 in thelatter position, the sleeve'112 is locked in its lowermost position withthe valve 113 fully open. Subsequently, one or more perforations areformed through the sleeve 112 at approximately the location P so thatthe chamber 115 may be in fluid communication with the pressure controlmeans of a retrievable valve assembly such as the assembly 89 previouslydescribed. It will be appreciated that the lock-down mechanism employedto mainpulate the sleeve 123 and the retrievable valve employed in theassembly 110 are similar to those previously described with reference tothe assembly 10. In addition, aspects of the assembly 110 notspecifically described are similar or analogous to those previouslydescribed with reference to the assembly 10. I

FIGS. 8 and 9 illustrate a modified form of the present inventionindicated generally at 210. The assembly 210 includes concentric, innerand outer tubing sections 211 and 212, respectively, which extendbetween the subsurface valve location and the well's surface. The innertubing section 211 connects with a tubular landing section 213 adaptedto hold a retrievable, surface operated safety valve assembly indicatedgenerally at 214. In operation, fluid pressure is supplied'to theassembly 210 through an annular space 215 formed be tween the inner andouter tubing members 211 and 212. The lower ends of the sections 211 and212 threadedly engage the upper end of a connecting sub 216. The lowerend of the sub 216 is in turn connected to a tubing string (notillustrated) which is in fluid communication with a subsurface,petroleum bearing formation.

Pressure in annular chamber 215 is communicated through radial ports 217formed through the walls of communicates with an annular passage 219sealed at its upper and lower ends respectively by O-rings 220 and 221carried on the retrievable valve assembly 214. The pressure in chamber219 is in turn communicated through ports 222 to an expansion chamber223 formed between a tubular valve housing body 224 and an internaltubular operating sleeve 225. Upper and lower sliding O-ring seals 226and 227, respectively, enclose the expansion chamber 223 to permit thesleeve 225 to move axially through the surrounding housing 224 whilemaintaining a continuous sliding seal between the two components.

In operation, the fluid pressure in the annular passage 215 is employedto expand the chamber 223 causing the sleeve 225 to shift downwardlycompressing a coil spring 228 carried between the sleeve 225 and thevalve housing 224. The initial downward movement of r the sleeve opens apressure bypass in the manner previ ously described with reference toFIGS. 58 and 78. Subsequent downward movement of the sleeve opens aflapper valve assembly indicated generally at 229 in the mannerpreviously described with reference to other modifications of theinvention. With the valve in the closed position illustrated in FIGS. 8Aand 8B, the flapper valve assembly 229 cooperates with an O-ring 221 tocompletely terminate effluent flow through the assembly.

In the event it becomes necessary to retrieve assembly 214 from itssubsurface location, a suitable retrieving mechanism is lowered throughthe tubing 211 and engaged with a retrieving shoulder 230. A lockingsleeve 231 is shifted downwardly by the retrieving mechanism to releaselocking dogs 232, in the manner previously described, to permit theassembly 214 to be removed to the surface.

During placement of the assembly 214, a lower restriction 232 limits thedownward axial movement of the landing section 213. A protective screen218 encir- 6 cles ports 217 to prevent debris from clogging orinterferring with the workings of the internal components of I theassembly to properly locate it with respect to the surrounding landingsection 213. When the proper location has been reached, the runningmechanism shifts the hold-down sleeve 231 upwardly in the mannerdescribed previously with reference to FIG. 5A to lock the dogs 232radially outwardly which in turn fixes the assembly 214 in positiomOtherfeatures in the placement, retrieval and operation of the assembly aresimilar to those described earlier with reference to the assemblies 10and 110. 4

While flapper valve closures have been employed to describe theoperation of the present invention, it will be appreciated that ballclosure members and other closures may be employed without departingfrom the teachings of the invention. Similarly, it will be understoodthat the annular control pressure flow passage described with referenceto FIGS. 8 and 9 may be employed in the embodiments described in FIGS.1-7.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof, and various changes in the size,shape and materials as well as in the details of the illustratedconstruction may be made within the scope of the appended claims withoutdeparting from the spirit of theinvention.

I claim:

1. A surface operated subsurface valve assembly for use in a wellcomprising:

a. subsurface valve means responsive to a control pressure forregulating flow of effluents through a well conduit;

b. control pressure passage means extending from said subsurface valvemeans toward the surface of said well for supplying control pressure tosaid valve means;

c. biasing means for urging said valve means to normally closed positionwherein effluent flow through said well conduit is terminated;

d. opening means operable by said control pressure for opening saidvalve means against the action of said biasing means;

e. pressure equalizing means operable by said control pressure forreducing the pressure differential across said valve means when saidvalve means is closed whereby said opening means may fully reopen saidvalve means; and

f. check valve means openable by control pressure in said controlpressure passage means for temporarily holding said subsurface valvemeans in open position while a relatively low control pressure ispresent in said passage means.

2. An assembly as defined in claim 1 wherein said valve means isretrievably positioned in said well conduit to permit placement andretrieval of said valve means from the well surface.

3. An assembly as defined in claim 2 wherein said control pressurepassage means includes a second well conduit encircling said first namedconduit to enclose a substantialy annular control pressure passagebetween said first mentioned conduit and said second conduit.

4. An assembly as defined in claim 1 wherein said control pressurepassage means includes a second well conduit encircling said first namedconduit to enclose a substantially annular control pressure passagebetween said first mentioned conduit and said second conduit.

5. An assembly as defined in claim 1 further including a second valvemeans retrievably positioned in said first mentioned valve means andoperable by said control pressure for regulating flow of effluentsthrough said well conduit.

6. An assembly as defined in claim 5 wherein said second valve meansincludes;

a. second biasing means for urging said second valve means to normallyclosed position;

b. second opening means operable by said control pressure for openingsaid second valve means against the action of said second biasing means;and

c. second pressure equalizing means operable by said control pressurefor reducing the pressure differential across said second valve meanswhen said second valve means is closed whereby said second opening meansmay fully reopen said second valve means.

7. An assembly as defined in claim 5 wherein said first mentioned valvemeans includes selectively operable means for retaining said firstmentioned valve means in open position irrespective of the controlpressure value.

8. An assembly as defined in claim 1 wherein said valve means includesselectively operable means for retaining said valve means in openposition irrespective of the control pressure value.

9. An assembly as defined in claim 1 further including:

a. a substantially tubular valve housing body means;

b. a substantially tubular control valve means, carried in said housingbody means.

c. a flapper valve closure element means operable by axial movement ofsaid control sleeve means to open or close said well conduit to effluentflow;

(1. coil spring biasing means carried concentrically between saidcontrol sleeve means and said housing means for normally biasing saidsleeve means in a direction to move said closure element means to closedposition; and

e. expansion chamber means communicating with said control pressure andoperable by said control pressure to expand and to move said sleevemeans in a direction moving said closure element means to open position.

10. An assembly as defined in claim 9 wherein said bypass means includesmeans operable upon limited movement of said sleeve means to open arelatively small pressure passage means commucating with the area insaid well conduit above and below said valve means.

11. A surface operated, subsurface valve assembly for use in a wellcomprising:

a. a first subsurface valve means responsive to a control pressure forregulating flow of effluents through a well conduit;

b. control pressure passage means extending from said subsurface valvemeans toward the surface of said well for supplying control pressure tosaid valve means;

c. biasing means for urging said valve means to normally closedposition;

d. opening means operable by said control pressure for opening saidvalve means against the action of said biasing means;

e. landing means in said valve means for landing a retrievable, secondvalve means in said first mentioned valve means;

f. means for operating said retrievable valve means by said controlpressure to regulate the flow of ef-- fluents through said conduit; and

g. check valves means openable by control pressure in said controlpressure passage means for temporily holding said subsurface valve meansin open position while a relatively low control pressure is present insaid passage means.

12. An assembly as defined in claim 11 wherein said first mentionedvalve is in fully open position and said retrievable valve means islanded and locked in said first mentioned valve means.

13. An assembly as defined in claim 12 wherein said second valve meansincludes:

a. second biasing means for urging said second valve means to normallyclosed position;

b. second opening means operable by said control pressure for openingsaid second valve means against the action of said second biasing means;and

c. a second pressure equalizing means operable by said control pressurefor reducing the pressure differential across said second valve meanswhen said second valve means is closed whereby said second opening meansmay fully reopen said second valve means.

14. An assembly as defined in claim 12 wherein said second valve meansfurther includes second pressure equalizing means operable by saidcontrol pressure for reducing the pressure differential across saidsecond valve means when said second valve means is closed whereby saidsecond opening means may fully reopen said second valve means.

15. An assembly as defined in claim 11 wherein said landing meansincludes selectively operable means for open or close said well conduitto effluent flow.

17. An assembly as defined in: claim 11 further includingpressureequalizing means operable by said control pressure for reducing thepressure differential across said valve means when said valve means isclosed whereby said opening means may fully reopen said valve means.

18. An assembly as defined in claim 1 wherein said check valve meansincludes a ball, a seat and a ball recess below said ball wherebyapplication of control pressure to said control pressure passage meansunseats said ball and permits said ball to fall into said ball re-Column Column Ccluinn Column Co l u mn Columh Collirfin (SEAL) Columnline line

12, line 8:

Attest:

line

line

UNITED STATES PATENT OFFICE CERTIFICATE OF CQRRECTION iiaten t N0. 3,73,93 Inl ento -(s) Dinning it is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Signed arid sealed this 1st day of January 1971;;

EDWARD M.FLETCHER,JR.

Attesting Officer Dated October 9, 1973 i change agiansc" to -against.

change "seal" to -seat.

change "22" to --12--.

change "t urular" to -tubular- Ch nge "1" to --10--.

change"sals" to -seals--. change "raidal' to -r'adial after "valve"insert -means-.

RENE D. TEGTD [EYER i Acting Commissioner of Patents,

OFiM Fir-1050 (10-69)

1. A surface operated subsurface valve assembly for use in a wellcomprising: a. subsurface valve means responsive to a control pressurefor regulating flow of effluents through a well conduit; b. controlpressure passage means extending from said subsurface valve means towardthe surface of said well for supplying control pressure to said valvemeans; c. biasing means for urging said vaLve means to normally closedposition wherein effluent flow through said well conduit is terminated;d. opening means operable by said control pressure for opening saidvalve means against the action of said biasing means; e. pressureequalizing means operable by said control pressure for reducing thepressure differential across said valve means when said valve means isclosed whereby said opening means may fully reopen said valve means; andf. check valve means openable by control pressure in said controlpressure passage means for temporarily holding said subsurface valvemeans in open position while a relatively low control pressure ispresent in said passage means.
 2. An assembly as defined in claim 1wherein said valve means is retrievably positioned in said well conduitto permit placement and retrieval of said valve means from the wellsurface.
 3. An assembly as defined in claim 2 wherein said controlpressure passage means includes a second well conduit encircling saidfirst named conduit to enclose a substantialy annular control pressurepassage between said first mentioned conduit and said second conduit. 4.An assembly as defined in claim 1 wherein said control pressure passagemeans includes a second well conduit encircling said first named conduitto enclose a substantially annular control pressure passage between saidfirst mentioned conduit and said second conduit.
 5. An assembly asdefined in claim 1 further including a second valve means retrievablypositioned in said first mentioned valve means and operable by saidcontrol pressure for regulating flow of effluents through said wellconduit.
 6. An assembly as defined in claim 5 wherein said second valvemeans includes; a. second biasing means for urging said second valvemeans to normally closed position; b. second opening means operable bysaid control pressure for opening said second valve means against theaction of said second biasing means; and c. second pressure equalizingmeans operable by said control pressure for reducing the pressuredifferential across said second valve means when said second valve meansis closed whereby said second opening means may fully reopen said secondvalve means.
 7. An assembly as defined in claim 5 wherein said firstmentioned valve means includes selectively operable means for retainingsaid first mentioned valve means in open position irrespective of thecontrol pressure value.
 8. An assembly as defined in claim 1 whereinsaid valve means includes selectively operable means for retaining saidvalve means in open position irrespective of the control pressure value.9. An assembly as defined in claim 1 further including: a. asubstantially tubular valve housing body means; b. a substantiallytubular control valve means, carried in said housing body means. c. aflapper valve closure element means operable by axial movement of saidcontrol sleeve means to open or close said well conduit to effluentflow; d. coil spring biasing means carried concentrically between saidcontrol sleeve means and said housing means for normally biasing saidsleeve means in a direction to move said closure element means to closedposition; and e. expansion chamber means communicating with said controlpressure and operable by said control pressure to expand and to movesaid sleeve means in a direction moving said closure element means toopen position.
 10. An assembly as defined in claim 9 wherein said bypassmeans includes means operable upon limited movement of said sleeve meansto open a relatively small pressure passage means communicating with thearea in said well conduit above and below said valve means.
 11. Asurface operated, subsurface valve assembly for use in a wellcomprising: a. a first subsurface valve means responsive to a controlpressure for regulating flow of effluents through a well conduit; b.control pressure passage means extending from said subsurface valvemeans toward the surface of said well for supplying control pressure tosaid valve means; c. biasing means for urging said valve means tonormally closed position; d. opening means operable by said controlpressure for opening said valve means against the action of said biasingmeans; e. landing means in said valve means for landing a retrievable,second valve means in said first mentioned valve means; f. means foroperating said retrievable valve means by said control pressure toregulate the flow of effluents through said conduit; and g. check valvesmeans openable by control pressure in said control pressure passagemeans for temporily holding said subsurface valve means in open positionwhile a relatively low control pressure is present in said passagemeans.
 12. An assembly as defined in claim 11 wherein said firstmentioned valve is in fully open position and said retrievable valvemeans is landed and locked in said first mentioned valve means.
 13. Anassembly as defined in claim 12 wherein said second valve meansincludes: a. second biasing means for urging said second valve means tonormally closed position; b. second opening means operable by saidcontrol pressure for opening said second valve means against the actionof said second biasing means; and c. a second pressure equalizing meansoperable by said control pressure for reducing the pressure differentialacross said second valve means when said second valve means is closedwhereby said second opening means may fully reopen said second valvemeans.
 14. An assembly as defined in claim 12 wherein said second valvemeans further includes second pressure equalizing means operable by saidcontrol pressure for reducing the pressure differential across saidsecond valve means when said second valve means is closed whereby saidsecond opening means may fully reopen said second valve means.
 15. Anassembly as defined in claim 11 wherein said landing means includesselectively operable means for retaining said valve means in openposition irrespective of the control pressure value.
 16. An assembly asdefined in claim 11 wherein said valve means includes: a. asubstantially tubular valve housing body means; b. a substantiallytubular control sleeve means carried in said housing body means; and c.a flapper valve closure element means operable by axial movement of saidcontrol sleeve means to open or close said well conduit to effluentflow.
 17. An assembly as defined in claim 11 further including pressureequalizing means operable by said control pressure for reducing thepressure differential across said valve means when said valve means isclosed whereby said opening means may fully reopen said valve means. 18.An assembly as defined in claim 1 wherein said check valve meansincludes a ball, a seat and a ball recess below said ball wherebyapplication of control pressure to said control pressure passage meansunseats said ball and permits said ball to fall into said ball recess.